It is known to use gas-liquid heat exchangers to cool compressed charge air in turbocharged internal combustion engines or in fuel cell engines, or to cool hot engine exhaust gases. For example, compressed charge air is typically produced by compressing ambient air. During compression, the air can be heated to a temperature of about 200° C. or higher, and must be cooled before it reaches the engine.
Various constructions of gas-cooling heat exchangers are known. For example, gas-cooling heat exchangers commonly have an aluminum core comprised of a stack of tubes or plate pairs, with each tube or plate pair defining an internal coolant passage. The tubes or plate pairs are spaced apart to define gas flow passages which are typically provided with turbulence-enhancing inserts to improve heat transfer from the hot gas to the liquid coolant.
In some gas-liquid charge air coolers, the core is “self-enclosing”, meaning that the sides of the gas flow passages are enclosed by the sides of the aluminum core. The gas inlet and outlet openings are typically provided at the open ends of the gas flow passages. Tanks are provided over the ends of the core to enclose the open ends of the core, to provide inlet and outlet openings, and to provide manifold spaces for the gas flow. However, it may be difficult to achieve a reliable crimp seal, particularly where the tanks and core are made of dissimilar materials. In addition, the tubes or plate pairs include flanges or other structures to enclose the sides of the core, increasing the material cost of the core.
There remains a need for gas-cooling heat exchangers which provide high reliability while avoiding excessive material and/or manufacturing costs.